Since the announcement of the successful synthesis of high-aspect-ratio-few-walled boron nitride nanotubes (FW-BNNTs) in 1995, little progress had been made until very recently in the scale-up of their synthesis. In spite of the theoretical capabilities of FW-BNNTs to provide high strength-to weight, high temperature resistance, piezo actuation, and radiation shielding (via the boron content), the aerospace industry has had to rely on micron-sized graphite or boron fibers for structural applications. Further, despite their very desirable properties, neither FW-BNNTs nor single wall carbon nanotubes are used widely in aerospace manufacturing, as the industry is generally unwilling to pay the premium price for these high performance materials.
The Inventors' recent work in the field of boron nitride nanotubes is described in various US. patent applications filed over the past several years. Inventors' U.S. patent application Ser. No. 12/152,414 filed May 14, 2008 and incorporated herein by reference in its entirety describes a process for the production of at least centimeter-long boron nitride nanotube strands or fibers. Inventors' U.S. patent application Ser. No. 12/322,591 filed Feb. 4, 2009 and incorporated herein by reference in its entirety describes an apparatus for the production of boron nitride nanotubes and a method of continuous removal of the formed boron nitride nanotubes from the synthesis chamber. Inventors' U.S. patent application Ser. No. 12/387,703 filed May 6, 2009 and incorporated herein by reference in its entirety describes a method for the production of fibrils and yarns. Inventor's U.S. patent application Ser. No. 13/199,101 filed Aug. 19, 2011 and incorporated herein by reference in its entirety for a feedstock delivery device describes the delivery of material to a reaction chamber or process-controlled zone.
BNNTs created by these methods possess a variety of properties which make them ideal for numerous research and commercial purposes. In particular, they may be formed into yarns for a variety of uses. It has been postulated that further modified BNNT yarns might have application in the area of superconducting wire.
Conventional superconducting wire is currently being used in an ever-expanding array of technical applications, such as in superconducting magnets and in superconducting (high-efficiency) motors. Conventional high-temperature superconducting wire exhibits superconducting properties at higher temperatures, e.g., >70K, than traditional lower temperature superconducting materials. Nonetheless, conventional high-temperature superconducting wire is very susceptible to stress fractures during fabrication, winding, and operational use. Similarly, other analogous materials such as cuprate high-temperature superconductors, are rather expensive to produce and also share a likelihood of stress failure. Alternatively, low temperature superconducting wire, e.g., wire composed of Niobium-Tin or Niobium-Titanium, typically requires a temperature no higher than 9K to achieve superconductivity. Use of these materials usually requires the application of helium refrigeration. Further, these low-temperature superconducting materials have poor thermal conductivity making them susceptible to material failure as a result of local thermal runaway during magnetic quench conditions.
A need therefore exists for superconducting material that achieves required superconducting goals while eliminating the aforementioned problems or limitations.